题目内容
(1)4.5×9.9+0.1;
(2)16-
+
-
;
(3)1.25×2.5×3.2;
(4)8.1÷(9-6.3×1.4);
(5)59+59×13+14×41.
解:(1)4.5×9.9+0.1,
=4.5×(10-0.1)+0.1,
=4.5×10-4.5×0.1+0.1,
=45-0.45+0.1,
=44.55+0.1,
=44.65;
(2)16-
+
-
,
=16-(
)
,
=16-1
,
=15
;
(3)1.25×2.5×3.2,
=(1.25×8)×(2.5×0.4),
=10×1,
=10;
(4)8.1÷(9-6.3×1.4),
=8.1÷(9-8.82),
=8.1÷0.18,
=45;
(5)59+59×13+14×41,
=59×(13+1)+14×41,
=59×14+14×41,
=(59+41)×14,
=100×14,
=1400.
分析:(1)4.5×9.9+0.1;转化为4.5×(10-0.1)+0.1,再运用乘法分配律进行简算;
(2)16-
+
-
;运用减法的运算性质进行简算;
(3)1.25×2.5×3.2;把3.2分解为8×0.4,再运用乘法交换律和结合律进行简算;
(4)8.1÷(9-6.3×1.4);根据小数四则混合运算的运算顺序,按照小数四则运算的计算法则进行计算;
(5)59+59×13+14×41.运用乘法分配律进行简算.
点评:此题主要考查小数、分数四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律和运算性质简便计算.
=4.5×(10-0.1)+0.1,
=4.5×10-4.5×0.1+0.1,
=45-0.45+0.1,
=44.55+0.1,
=44.65;
(2)16-



=16-(


=16-1

=15

(3)1.25×2.5×3.2,
=(1.25×8)×(2.5×0.4),
=10×1,
=10;
(4)8.1÷(9-6.3×1.4),
=8.1÷(9-8.82),
=8.1÷0.18,
=45;
(5)59+59×13+14×41,
=59×(13+1)+14×41,
=59×14+14×41,
=(59+41)×14,
=100×14,
=1400.
分析:(1)4.5×9.9+0.1;转化为4.5×(10-0.1)+0.1,再运用乘法分配律进行简算;
(2)16-



(3)1.25×2.5×3.2;把3.2分解为8×0.4,再运用乘法交换律和结合律进行简算;
(4)8.1÷(9-6.3×1.4);根据小数四则混合运算的运算顺序,按照小数四则运算的计算法则进行计算;
(5)59+59×13+14×41.运用乘法分配律进行简算.
点评:此题主要考查小数、分数四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律和运算性质简便计算.

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